I'm taking Alli along with a low fat diet (most of the time) and I've lost half a stone, as opposed to being on the same diet and losing nothing. I do notice if I splurge on a big meal it gets through my system much quicker - to put it politely - I'd definitely say it makes a difference although it's slow and steady. In response to Brenda, Alli is different to the other two in that it has been medically tested and prescribed by doctors for quite some time, so it's not some miracle pill being touted, it has been shown to work and to work safely. It prevents your body absorbing some of the fat you take in, it is not an appetite suppressant and it encourages you to eat a low fat diet or you end up with diarrhoea.